Shopsmith to route mortise and tenon joints??

otee453 · Post by **otee453** » Sat Feb 28, 2009 10:32 am

I will add,

I tried brad point drill bits and forsner bits both in drilling mortises. I was very unhappy with the flex (too much flex) in the brad point bits, the forsner bit was more solid, but drilled slowly,

A solid carbide 1/4" or 3/8" upcut spiral bit, works SUPER!

Ed in Tampa · Post by **Ed in Tampa** » Sat Feb 28, 2009 10:57 am

While I'm an advocate of using the Shopsmith as a router in some instances I haven't done much mortising with the SS in router mode. However I would think, depending on a many factors, a carbide upcut spiral bit with a piercing tip would be the cat's meow to drill perfectly placed near overlapping holes that could then be cleaned up using the bit in router fashion. Even if you didn't want to drill near overlapping holes I would certainly drill an entry (beginning of the mortise cut) and exit hole (end of the mortise cut) before I routed the rest of the mortise out.

An upcut piercing spiral bit has a tip that I would equate to a forster bit and fairly stout body that keeps defaction to a minium. The up cut flutes carries the chips out of the hole and because of the many flutes and carbide construction it is made to turn faster than a forster bit thus you have less chance of deflection.

For tendons I believe cutting them on tablesaw or bandsaw would be best.

I cut mortises many different ways and frankly no one method appears superior to another in every situation.

calver · Post by **calver** » Wed Mar 04, 2009 4:18 pm

The woodwhisperer has a good video on alternative methods of mortise and tenon joinery. Some techniques are applicable to using shopsmith and some are not. Worth looking at. I think it might be session #10.

Dave C.

edflorence · Post by **edflorence** » Wed Mar 04, 2009 11:48 pm

Tenons: Table saw and miter gage or cross-cut table. I use a block on the fence to set the distance to the shoulders and cut them first. After that, I pull the workpiece away from the blade gradually, taking a series of nibbling cuts. This leaves a rough surface but not too bad and is quicker than setting up the bandsaw and, imho, safer and faster than the tenon jig. Once in a while I will set up a dado blade, but generally not. The nibbling cuts save me a blade change and really don't take much extra time. A gentle paring cut with a chisel after the sawing cleans up the tenon faces. While the chisel is out, I also take a very very thin paring from the shoulder to the tenon for a slightly undercut shoulder.

Mortise: Drill press, fence, fostner bit. I set up distance stops, or sometimes just tape with pencil marks, on the fence then drill the end holes first, followed by a series of overlapping holes between the ends, then clean up the mortise walls with a chisel. I used to use a corner chisel on the mortise corners but quit doing that a while ago and now just take a pass or two on the tenon edges with a rasp to round them over to fit the radiused ends of the mortise. I drill the mortise out to a depth slightly greater than the tenon length to give the excess glue a place to go and also to be sure the tenon won't bottom out.

I like this system because its simple, requires few setups and no jigs and, near as I can tell by how the joints have held up, works fine.

reible · Post by **reible** » Thu Mar 05, 2009 11:03 pm

Thanks for the additional replies! This is still an open question so anyone else that wants to explain their method(s) feel free to do so. More information is way better then less in this case.

Ed

JPG · Post by **JPG** » Thu Mar 05, 2009 11:52 pm

This is going to sound weird, and time consuming, but it does work. A problem with a mortise made with a SS router bit is that the ends are a semi-circle. By routing(similar to drilling) two holes in the tenon piece before cutting the tenon at the distance apart = to the location of the 'ends of the mortise' you can insert two dowels in the mortise and slide the tenon between them. This also reduces the need to control the depth of the end shoulder cut(no shoulder[the dowel hole intersects]). The dowel hole in the tenon piece can be 'drilled' deeper than the actual tenon. The mortise piece can be be deeper 'drilled' similarly.
More work, more exacting, but less stressful than trying to make 'square' holes.

Another approach!:)

shophaven · Post by **shophaven** » Sat Mar 07, 2009 7:00 pm

Recently I built a coffee table project out of scrap construction-grade 2x4's and plywood - mostly as a prototype and to learn from the experience before I put out heavy cash for expensive wood. Not having the mortising jig or router chuck, I cut the mortises using a 3/8" Forstner bit - with the SS in the drill press mode. I would not do this again - the table is simply not steady enough. I noticed in Nick's demo video, he used the extension legs to steady up the table using the mortising attachment. I think the horizontal mode would work better. I, too, left the ends of each mortise slot rounded and just rounded off the tenons to fit. Some hand smoothing of the mortise slots was required with a chisel.

The 1 1/2" long tenons were cut with the table saw using repetitive passes with a stacked dado blade - again smoothed up with a chisel.

On the next go-around, I would build a jig to ensure exact placement of the mortises on each leg, and I would insure the the legs are exactly square in crossection - not stacked 2x4's - resulting in a rectangular crossection. Oh well - that was the reason for the prototype! Pictures attached.

a1gutterman · Post by **a1gutterman** » Sat Mar 07, 2009 7:10 pm

Hi shophaven,

Welcome to these forums. The table looks pretty nice. After having done that, now you can make a duplicate using some nice hardwood.

otee453 · Post by **otee453** » Sat Mar 07, 2009 8:11 pm

JPG40504 wrote:This is going to sound weird, and time consuming, but it does work. A problem with a mortise made with a SS router bit is that the ends are a semi-circle. By routing(similar to drilling) two holes in the tenon piece before cutting the tenon at the distance apart = to the location of the 'ends of the mortise' you can insert two dowels in the mortise and slide the tenon between them. This also reduces the need to control the depth of the end shoulder cut(no shoulder[the dowel hole intersects]). The dowel hole in the tenon piece can be 'drilled' deeper than the actual tenon. The mortise piece can be be deeper 'drilled' similarly.
More work, more exacting, but less stressful than trying to make 'square' holes.

Another approach!:)

I haven't ever heard of that one. Its a good idea for a really strong joint.

charlese · Post by **charlese** » Sat Mar 07, 2009 9:28 pm

Hi, shophaven! Thank you for posting on the Forum and even better, Thanks for posting photos of furniture you made. Your table look real good! Don't really see a big issue with the joints. What did you use for the top surface? I love the way the top is hinged!

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